ABSTRACT
BACKGROUND: The coronavirus disease 2019 pandemic restricted movement of individuals and altered provision of health care, abruptly transforming health care-use behaviors. It serves as a natural experiment to explore changes in presentations for surgical diseases including acute appendicitis. The objective was to determine if the pandemic was associated with changes in incidence of acute appendicitis compared to a historical control and to determine if there were associated changes in disease severity. METHODS: The study is a retrospective, multicenter cohort study of adults (N = 956) presenting with appendicitis in nonpandemic versus pandemic time periods (December 1, 2019-March 10, 2020 versus March 11, 2020-May 16, 2020). Corresponding time periods in 2018 and 2019 composed the historical control. Primary outcome was mean biweekly counts of all appendicitis presentations, then stratified by complicated (n = 209) and uncomplicated (n = 747) disease. Trends in presentations were compared using difference-in-differences methodology. Changes in odds of presenting with complicated disease were assessed via clustered multivariable logistic regression. RESULTS: There was a 29% decrease in mean biweekly appendicitis presentations from 5.4 to 3.8 (rate ratio = 0.71 [0.51, 0.98]) after the pandemic declaration, with a significant difference in differences compared with historical control (P = .003). Stratified by severity, the decrease was significant for uncomplicated appendicitis (rate ratio = 0.65 [95% confidence interval 0.47-0.91]) when compared with historical control (P = .03) but not for complicated appendicitis (rate ratio = 0.89 [95% confidence interval 0.52-1.52]); (P = .49). The odds of presenting with complicated disease did not change (adjusted odds ratio 1.36 [95% confidence interval 0.83-2.25]). CONCLUSION: The pandemic was associated with decreased incidence of uncomplicated appendicitis without an accompanying increase in complicated disease. Changes in individual health care-use behaviors may underlie these differences, suggesting that some cases of uncomplicated appendicitis may resolve without progression to complicated disease.